Monolithic bullet projectile for rifle firearms and method of making same

ABSTRACT

The invention comprises a monolithic bullet projectile for rifle firearms (FIG.  1 ), having cylindrical profile of front guiding section (CP) of a diameter which is lower than or equal to a diameter of lands (øP) of the rifled bore of the firearm barrel, with specific short head (CG) of half-circle or cone shape, and a method of making same. It is characterized in that the centre of gravity (SC) is situated in the front, cylindrical guiding section of the bullet, and the back trailing section (CW), situated behind the centre of gravity (SC) of the whole bullet, has radial profiling comprising the relieving grooves (RO) of a diameter lower than a diameter of lands (øP) of the rifled bore of the firearm barrel and the trailing rings (PW) of a diameter which is equal to or lower than a diameter of the rifles (øB) of the rifled bore of the firearm barrel, situated in the following order: trailing ring-relieving groove-trailing ring or multiplication of that configuration, so that the total number of the trailing rings (PW) of the bullet is always twice as high as the number of relieving grooves (RO) of the bullet. A method of making the bullet according to the invention is characterized in that the guiding section of the bullet (CP) is calibrated independently up to a diameter which is lower than or equal to a diameter of lands (øP) of the rifled bore of the barrel, and the radial profiling of the trailing section of the bullet (CW), comprising the relieving grooves (RO) and trailing rings (PW), is made in a single technological operation, applying for the making of trailing rings (PW) the effect of upsetting of the homogeneous material of the bullet along the edge of the radial relieving groove (RO) while the trailing section of the bullet (CW) is calibrated independently up to a diameter which is lower than or equal to a diameter of the rifles (øB) of the rifled bore of the barrel.

TECHNICAL FIELD

The invention relates to a monolithic bullet projectile for riflefirearms and to a simple method of making same.

BACKGROUND ART

Heavy, blunt head projectiles made from copper or brass, of stable massand shape known as full monolithic projectiles (Solid or Monobloc type)are commonly used, especially in huntsman's practice (Manfred R.Rosenberger “Huntsman's ammunition; Structure; Behavior inside thetarget; Application” Bellona Ed., Warsaw 2009, pp. 198-206). Suchprojectiles maintain stable ballistic flight trajectory due togyroscopic stabilization.

BRIEF SUMMARY OF THE INVENTION

The invention relates to a monolithic bullet projectile for riflefirearms, having cylindrical profile of front guiding section (CP) withspecific short head (CG) of half-circle or cone shape, and the backtrailing section (CW), situated behind the centre of gravity (SC) of thewhole bullet, having radial profiling comprising the relieving grooves(RO) and the trailing rings (PW), situated in the following order:trailing ring-relieving groove-trailing ring or multiplication of thatconfiguration.

The invention relates further to a method of making the bullet accordingto the invention wherein the guiding section of the bullet (CP) iscalibrated independently up to a diameter which is lower than or equalto a diameter of lands (øP) of the rifled bore of the barrel, and theradial profiling of the trailing section of the bullet (CW), comprisingthe relieving grooves (RO) and trailing rings (PW), is made in a singletechnological operation, applying for the making of trailing rings (PW)the effect of upsetting of the homogeneous material of the bullet alongthe edge of the radial relieving groove (RO) while the trailing sectionof the bullet (CW) is calibrated independently up to a diameter which islower than or equal to a diameter of the rifles (øB) of the rifled boreof the barrel.

According to the invention, independent calibration of a diameter oflands (øP) and of a diameter of the rifles (øB) allows for individualfitting of the external dimensions of the bullet to any barrel of therifle firearm, even if the wear of the rifle is significant which iscrucial in the process of extending the lifetime of the firearm.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is described in detail in reference to the accompanyingdrawings, in which:

FIG. 1 presents a half-section of the bullet projectile;

FIG. 2 presents a cross-section of the typical rifled barrel bore of afirearm;

FIG. 3 presents a scheme of the operation of cutting the startingmaterial for the bullet and of shaping the bullet head—front view (left)and side view (right);

FIG. 3a presents the start of the operation of cutting the weighedbillet;

FIG. 3b presents the end of the operation of cutting the weighed billet;

FIG. 4 presents scheme of the operation of calibrating the guidingsection of the bullet, including finishing the bottom surface;

FIG. 5 presents scheme of the operation of cutting the relieving groovesincluding simultaneous profiling of the guiding rings of thebullet—front view (left) and side view (right);

FIG. 5a presents the start of the operation of cutting the relievinggrooves;

FIG. 5b presents the end of the operation of cutting the relievinggrooves;

FIG. 6 presents the scheme of the operation of calibrating the trailingsection of the bullet.

DISCLOSURE OF THE INVENTION

According to the invention the bullet projectile made fully of copper orcopper alloys, as shown in a half-section in FIG. 1, has typicalcylindrical profile of guiding section (CP) with very short head (CG) ofhalf-circle or cone shape. Trailing section of the bullet (CW), situatedin its back behind its centre of gravity (SC), has radial profilingcomprising the relieving grooves (RO) of a diameter which is lower thana diameter of the lands (øP) of the rifled barrel bore and the trailingrings (PW) of a diameter which is lower than or equal to a diameter ofthe rifles (øB) of the rifled barrel bore. Short bottom section of thebullet (CD) is terminated with a truncated cone or with a flat.

A cross-section of typical rifled barrel bore of a firearm is shown inFIG. 2.

Relieving grooves (RO) diminish the radial stiffness of bullet solidbody, resulting in reduction of force needed to overcome the resistanceof rifled barrel bore to the bullet driving along.

Trailing rings (PW) which are responsible for providing gyroscopicstabilization effect to the bullet, increase tightness between bulletbody and rifled barrel bore, resulting in reduction of working pressurelosses of gunpowder gases in the back space of the barrel.

Situation of trailing rings (PW) in the back section of the bullet,behind the centre of gravity (SC), results in improvement of ballisticcharacteristics of the bullet flight after the bullet leaves the barrelbore, through providing additional fin stabilization due to increasingthe resistance to air flowing around the extended back of the bullet, asdisclosed in PI Patent PL 211026 B1 published on 30 Mar. 2012 WUP March2012.

Guiding section of the bullet (CP) comprises a smooth cylindrical areaof a diameter equal to or lower than a diameter of the lands (øP) of therifled barrel bore, providing a slide fit of that section of the bulletin the barrel bore which improves characteristics of interior ballisticsthrough diminishing the resistance related to surface friction duringdriving of the bullet along the barrel bore.

Short head section of the bullet (CG) which can comprise a sphericalcap, a hemisphere, a truncated hemisphere, a cone, a truncated cone or aflat, ensures a stable flight of the bullet when it flies through lighthurdles (shrubs, grass) due to edge stabilization which is createdduring flight because of the asymmetrical air pressure growing on thehead of bullet. This is crucial when the bullet is used in huntsman'sfirearms. In the same time the sharp edge which is formed on the bulletin the spot where the bullet head (CG) continues into cylindricalguiding section of the bullet (CP) ensures ideally cut shape of thebullet hole in the target. This is crucial when the bullet is used insport firearms.

Design of the bullet projectile of the invention improves (as comparedto the state of the art) interior ballistics characteristics (inside thebarrel bore), exterior ballistics characteristics (in the air) and finalballistics characteristics (in the target) and ensures fullstabilization of the bullet flight path through combining the effects ofgyroscopic stabilization, fin stabilization and edge stabilization,which cannot be achieved using the known so far designs of bulletprojectiles for rifle firearms.

According to the invention it is possible to make a monolithic bulletprojectile for rifle firearms in economical way (wasteless) and simpleway (without applying complex machinery and devices).

According to the invention, a method of making a monolithic bulletprojectile is characterized by simplicity of technological process whichcan be implemented in workshop conditions, even without mechanicaldrive. This is crucial in the process of ammunition reloading in thehousehold or in the field for hunting or sport purpose.

According to the invention the following four technological operationsare suitable for making a monolithic bullet projectile of any caliberand weight: cutting the weighed billet, calibrating the guiding sectionof the bullet, cutting the relieving grooves, calibrating the trailingsection of the bullet.

Operation I of Cutting the Weighed Billet

Scheme of the operation of cutting the starting material for the bulletand of shaping the bullet head is shown in FIG. 3. Front view of cuttingand shaping operation is show on the left side of FIG. 3. Side view ofcutting and shaping operation is shown on the right side of FIG. 3.

Cutting (which includes shaping of bullet head) of the starting material(1), supplied in the form of either a wire or a rod, of a diameter whichis equal to or higher than a diameter of lands of final barrel bore ofthe rifle firearm, to obtain billets (2) corresponding to the requiredbullet weight, is performed through combining the rotary motion (ω) ofstarting material and radial motion (r) of the adequately shaped cuttingroll (3), against the pair of supporting rolls (4).

The start of cutting operation is shown in FIG. 3 a.

The end of cutting operation is shown in FIG. 3 b.

Operation II of Calibrating the Guiding Section of the Bullet.

Scheme of the operation of calibrating the guiding section of thebullet, including finishing the bottom surface, is shown in FIG. 4.

Calibrating the guiding section of the bullet (2) up to a diameter whichis equal to or lower than a diameter of the lands (øP) of the finalbarrel bore of the firearm is made by redrawing (s) with a punch (5) ina die (6) having a cone-shaped input hole and a cylindrical calibratinghole (øP). Pressing the head of the punch (5) against the bottom sectionof the bullet results in simultaneous finishing of the surface of thebullet's bottom (back flat).

Operation III of Cutting the Relieving Grooves.

Scheme of the operation of cutting the relieving grooves includingsimultaneous profiling of the guiding rings of the bullet is shown inFIG. 5. Front view of operation of cutting the relieving grooves isshown on the left side of FIG. 5. Side view of operation of cutting therelieving grooves is shown on the right side of FIG. 5.

Cutting the relieving grooves on the guiding section of the bullet,including simultaneous profiling of the guiding rings (through upsettingof the bullet material along both edges of the radial groove which isbeing cut off), is made by combining the rotary motion (ω) of the billet(2) and radial motion (r) of the cutting roll or set of cutting rolls(7) against a pair of cylindrical supporting rolls (8). Cutting therelieving grooves should be done such that the depth of the cuts shouldgo deeper than the diameter of the lands of the final barrel bore of thefirearm, and the height of the upsetting of the guiding rings should behigher than the depth of the rifles of the final barrel bore of thefirearm.

The start of cutting operation is show in FIG. 5 a.

The end of cutting operation is shown in FIG. 5 b.

Operation IV of Calibrating the Trailing Section of the Bullet.

Scheme of the operation of calibrating the trailing section of thebullet is shown in FIG. 6.

Calibrating the trailing section of the bullet (2) formed of series oftrailing rings, up to a diameter which is equal to or lower than adiameter of the rifles (øB) of the final barrel bore is made by one stepredrawing (s) using a punch (9) in a die (10) with an input cone-shapedhole and a cylindrical calibrating hole (øB).

According to the invention, independent calibration of a diameter oflands (øP) and of a diameter of the rifles (øB) allows for individualfitting of the external dimensions of the bullet to any barrel of therifle firearm, even if the wear of the rifle is significant which iscrucial in the process of extending the lifetime of the firearm.

What is claimed is:
 1. A monolithic bullet projectile for riflefirearms, having cylindrical profile of front guiding section (CP) of adiameter which is lower than or equal to a diameter of lands (øP) of therifled bore of the firearm barrel, with specific short head (CG) shapedas a spherical cap, a hemisphere, a truncated hemisphere, a cone, atruncated cone or a flat, wherein the centre of gravity (SC) of thebullet is situated in the cylindrical front guiding section of thebullet.
 2. A monolithic bullet projectile according to claim 1, whereinthe back trailing section (CW), situated behind the centre of gravity(SC) of the whole bullet, has radial profiling comprising the relievinggrooves (RO) of a diameter lower than a diameter of lands (øP) of therifled bore of the firearm barrel and the trailing rings (PW) of adiameter which is equal to or lower than a diameter of the rifles (øB)of the rifled bore of the firearm barrel, situated in the followingorder: trailing ring-relieving groove-trailing ring or multiplication ofthat configuration, so that the total number of the trailing rings (PW)of the bullet is always twice as high as the number of relieving grooves(RO) of the bullet.
 3. A method of making a monolithic bullet projectilefor rifled firearms, made of copper or copper alloys, wherein radialprofiling of the trailing section of the bullet (CW) comprising therelieving grooves (RO) and trailing rings (PW), situated in thefollowing order: trailing ring-relieving groove-trailing ring ormultiplication of that configuration, is made in a single technologicaloperation, applying for the making of trailing rings the effect ofupsetting of the homogeneous material of the bullet (2) along the edgeof the radial relieving groove, using a cutting roll or a set of cuttingrolls (7) acting together with cylindrical rolls (8) supporting thebullet material.
 4. A method according to claim 3, wherein the guidingsection of the bullet (CP) is calibrated independently up to a diameterwhich is lower than or equal to a diameter of lands (øP) of the rifledbore of the barrel, and the trailing section of the bullet (CW) iscalibrated independently up to a diameter which is lower than or equalto a diameter of rifles (øB) of the rifled bore of the barrel.